docs: def rot2(theta):
      """
      Args:
          theta (float): Angle in radians
      Return:
          Rotation matrix of angle theta around the Y-axis
      """
      return np.array([
          [np.cos(theta), 0, -np.sin(theta)],
          [0, 1, 0],
          [np.sin(theta), 0, np.cos(theta)]
      ])